hello again and thank you for your replie
hmm..I've installed 2.2 now, but unfortunatly the only sucess is
that the error-message changed a little bit when trying to upload a grouplogo:
* JFolder::create: Could not create directory
* Group failed to save! Error: Error occurred during the moving of the uploaded file. Method: Move
I'm really sorry, maybe it's just some absolute basic problem with my configuration, but I'm not aware of it - any idea?